1. Field of the Invention
The present invention relates to a fuel cell stack including a plurality of fuel cells and a first end plate and a second end plate each having a laterally elongated shape. Each of the fuel cells is formed by stacking a membrane electrode assembly and a separator horizontally in a stacking direction. The membrane electrode assembly includes a pair of electrodes and an electrolyte interposed between the electrodes. The first end plate and the second end plate are provided at both ends of the fuel cells in the stacking direction.
2. Description of the Related Art
For example, a solid polymer electrolyte fuel cell includes a power generation cell formed by sandwiching a membrane electrode assembly (MEA) between separators. The membrane electrode assembly includes an electrolyte membrane, an anode provided on one surface of the electrolyte membrane, and a cathode provided on the other surface of the electrolyte membrane. The electrolyte membrane is a polymer ion exchange membrane. In the fuel cell, normally a predetermined number of power generation cells are stacked together to form a fuel cell stack, e.g., mounted in a vehicle.
In the case where the fuel cell stack is used, in particular, in a vehicle, it is required to stack a considerably large number of power generation cells. Thus, the power generation cells need to be positioned, and held together precisely and securely.
In this regard, for example, a fuel cell stack disclosed in Japanese Laid-Open Patent Publication No. 2006-040845 (hereinafter referred to as conventional technique) is known. In the fuel cell stack, as shown in FIG. 8, a plurality of fuel cells each having a polygonal shape are stacked together to from a fuel cell stack body. Current collecting plates are provided at both ends of the fuel cell stack body, insulating plates are provided outside the current collecting plates, and end plates 1 are provided outside the insulating plates. The fuel cell stack is formed in a polygonal columnar shape as a whole.
Load support members 4 are provided to cover corners 2 of the fuel cell stack. Each of the load support members 4 includes a corner cover portion 3 having an L shape in cross section to cover the ridge line R of the corner 2. Load maintaining member 5 is provided for the load support member 4, for maintaining a load applied to components between the end plates 1 at both ends.